Methods and systems for a ranging protocol

ABSTRACT

Disclosed are processes, devices and systems for exchanging messages between devices in support of measuring ranges between devices. In one particular implementation, a first wireless transceiver device may transmit one or more fine timing measurement (FTM) messages to a second wireless transceiver device, and receive a message acknowledging receipt of at least one of the one or more FTM messages. The first wireless transceiver device may authenticate the received message as being transmitted from the second wireless transceiver device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application claims the benefit of and priority to co-pendingU.S. Provisional Patent Application No. 62/292,172, filed Feb. 5, 2016,entitled “METHODS AND SYSTEMS FOR A RANGING PROTOCOL,” and to U.S.Provisional Patent Application No. 62/294,890, filed Feb. 12, 2016,entitled “METHODS AND SYSTEMS FOR A RANGING PROTOCOL,” both of which areassigned to the assignee hereof and which are incorporated herein intheir entirety by reference.

BACKGROUND

Field

Embodiments described herein are directed to obtaining measurements ofsignals acquired from a mobile transmitter.

Information:

Satellite positioning systems (SPSs), such as the global positioningsystem (GPS), have enabled navigation services for mobile handsets inoutdoor environments. Likewise, particular techniques for obtainingestimates of positions of mobile device in indoor environments mayenable enhanced location based services in particular indoor venues suchas residential, governmental or commercial venues. For example, a rangebetween a mobile device and a transceiver positioned at a fixed locationmay be measured based, at least in part, on a measurement of a roundtrip time (RTT) measured between transmission of a first message from afirst device to a second device and receipt of a second message at thefirst device transmitted in response to the first message.

SUMMARY

Briefly, one particular implementation is directed to a methodcomprising, method, at a first wireless transceiver device, comprising:transmitting a first fine timing measurement (FTM) message addressed toa second wireless transceiver device; and conditionally authenticating areceived message as being transmitted by the second wireless transceiverdevice and acknowledging receipt of the first FTM message.

Another particular implementation is directed to a first wirelessstation (STA), comprising: a wireless transceiver to transmit messagesto and receive messages from a communication network; and a processorcoupled to the wireless transceiver, the processor being configured to:initiate transmission of a first fine timing measurement (FTM) messagethrough the wireless transceiver, the first FTM message being addressedto a second STA; and conditionally authenticate a message received atthe wireless transceiver as being transmitted by the second STA andacknowledging receipt of the first FTM message.

Another particular implementation is directed to a first wirelesstransceiver device, comprising: means for transmitting a first finetiming measurement (FTM) message addressed to a second wirelesstransceiver device; and means for conditionally authenticating areceived message as being transmitted by the second wireless transceiverdevice and acknowledging receipt of the first FTM message.

Another particular implementation is directed to a non-transitorystorage medium comprising computer readable instructions stored thereonwhich are executable by a processor of a first wireless transceiverdevice to: initiate transmission of a first fine timing measurement(FTM) message, the first FTM message being addressed to a secondwireless transceiver device; and conditionally authenticate a receivedmessage as being transmitted by the second wireless transceiver deviceand acknowledging receipt of the first FTM message.

Another particular implementation is directed to a method at a firstwireless transceiver device comprising: transmitting a firstacknowledgement message indicating receipt of a first fine timingmeasurement (FTM) message transmitted by a second wireless transceiverdevice; and receiving a second FTM message from the second wirelesstransceiver, the second FTM message comprising one or more parametersbased, at least in part, on a time of an authenticated receipt of thefirst acknowledgement message at the second wireless transceiver device.

Another particular implementation is directed to a first wirelessstation (STA) comprising: a wireless transceiver to transmit messages toand received messages from a communication network; and a processorcoupled to the wireless transceiver, the processor being configured to:initiate transmission of a first acknowledgement message through thewireless transceiver indicating receipt of a first fine timingmeasurement (FTM) message transmitted by a second STA and received atthe wireless transceiver; and obtain a second FTM message received atthe wireless transceiver from the second STA, the second FTM messagecomprising one or more parameters based, at least in part, on a time ofan authenticated receipt of the first acknowledgement message at thesecond STA.

Another particular implementation is directed to a non-transitorystorage medium comprising computer readable instructions stored thereonwhich are executable by a processor of a first wireless transceiverdevice to: initiate transmission of a first acknowledgement messageindicating receipt, at the first wireless transceiver device, of a firstfine timing measurement (FTM) message transmitted by a second wirelesstransceiver device; and obtain a second FTM message received at thefirst wireless transceiver device from the second wireless transceiver,the second FTM message comprising one or more parameters based, at leastin part, on a time of an authenticated receipt of the firstacknowledgement message at the second wireless transceiver device.

Another particular implementation is directed to a first wirelesstransceiver device comprising: means for transmitting a firstacknowledgement message indicating receipt of a first fine timingmeasurement (FTM) message transmitted by a second wireless transceiverdevice; and means for receiving a second FTM message from the secondwireless transceiver, the second FTM message comprising one or moreparameters based, at least in part, on a time of an authenticatedreceipt of the first acknowledgement message at the second wirelesstransceiver device.

It should be understood that the aforementioned implementations aremerely example implementations, and that claimed subject matter is notnecessarily limited to any particular aspect of these exampleimplementations.

BRIEF DESCRIPTION OF THE DRAWINGS

Claimed subject matter is particularly pointed out and distinctlyclaimed in the concluding portion of the specification. However, both asto organization and/or method of operation, together with objects,features, and/or advantages thereof, it may best be understood byreference to the following detailed description if read with theaccompanying drawings in which:

FIG. 1 is a system diagram illustrating certain features of a systemcontaining a mobile device, in accordance with an implementation.

FIGS. 2 and 3 are message flow diagrams according to particularembodiments.

FIG. 4A is a flow diagram of a process to authenticate acknowledgementmessages according to an embodiment.

FIG. 4B is a flow diagram of a process to process fine timingmeasurement (FTM) messages according to an embodiment.

FIGS. 5 and 6 show fields of media access control (MAC) header of amessage transmitted between wireless transceiver devices according to anembodiment.

FIGS. 7 and 8 are message flow diagrams according to an embodiment.

FIG. 9 is a schematic block diagram illustrating an exemplary device, inaccordance with an implementation.

FIG. 10 is a schematic block diagram of an example computing system inaccordance with an implementation.

Reference is made in the following detailed description to accompanyingdrawings, which form a part hereof, wherein like numerals may designatelike parts throughout that are corresponding and/or analogous. It willbe appreciated that the figures have not necessarily been drawn toscale, such as for simplicity and/or clarity of illustration. Forexample, dimensions of some aspects may be exaggerated relative toothers. Further, it is to be understood that other embodiments may beutilized. Furthermore, structural and/or other changes may be madewithout departing from claimed subject matter. References throughoutthis specification to “claimed subject matter” refer to subject matterintended to be covered by one or more claims, or any portion thereof,and are not necessarily intended to refer to a complete claim set, to aparticular combination of claim sets (e.g., method claims, apparatusclaims, etc.), or to a particular claim. It should also be noted thatdirections and/or references, for example, such as up, down, top,bottom, and so on, may be used to facilitate discussion of drawings andare not intended to restrict application of claimed subject matter.Therefore, the following detailed description is not to be taken tolimit claimed subject matter and/or equivalents.

DETAILED DESCRIPTION

References throughout this specification to one implementation, animplementation, one embodiment, an embodiment, and/or the like meansthat a particular feature, structure, characteristic, and/or the likedescribed in relation to a particular implementation and/or embodimentis included in at least one implementation and/or embodiment of claimedsubject matter. Thus, appearances of such phrases, for example, invarious places throughout this specification are not necessarilyintended to refer to the same implementation and/or embodiment or to anyone particular implementation and/or embodiment. Furthermore, it is tobe understood that particular features, structures, characteristics,and/or the like described are capable of being combined in various waysin one or more implementations and/or embodiments and, therefore, arewithin intended claim scope. In general, of course, as has always beenthe case for the specification of a patent application, these and otherissues have a potential to vary in a particular context of usage. Inother words, throughout the patent application, particular context ofdescription and/or usage provides helpful guidance regarding reasonableinferences to be drawn; however, likewise, “in this context” in generalwithout further qualification refers to the context of the presentpatent application.

As discussed below, particular message flows may enable effective andefficient measurements of a range in connection with a transmission ofmessages between wireless stations (STAs). In a particular example, aSTA may comprise any one of several types of transceiver devices suchas, for example, a mobile user station (e.g., smartphone, notebookcomputer, tablet computer, etc.) or wireless service access device(e.g., wireless local area network (WLAN) access point, personal areanetwork (PAN) or femto cell). Particular message flows and fields inmessage frames may enable obtaining round-trip time (RTT) or time offlight (TOF) measurements with sufficient accuracy for measuring a rangebetween the wireless STAs using fewer messages, for example. Such ameasured range may be used in any one of several applications includingpositioning operations, for example.

Transmissions of messages between STAs for the measurement of RTTtypically occurs in addition to other message traffic supporting otherapplications such as voice, video, HTTP, data, just to provide a fewexamples. Accordingly, in dense operating environments, messagingbetween STAs for the measurement of RTT may increase congestion andcontention for wireless link resources. In particular implementationsdiscussed below, particular positioning techniques may be supported bymeasuring a TOF for the transmission of a message between STAs usingfewer messages than typical techniques used for measuring RTT. Accordingto an embodiment, TOF may be measured for individual messages in a“burst” of messages transmitted close in a sequence. Combining multipleTOF measurements from a burst of received messages may enable reductionin measurement errors, for example.

According to an embodiment, as shown in FIG. 1, mobiles device 100 a or100 b may transmit radio signals to, and receive radio signals from, awireless communication network. In one example, a mobile device 100 maycommunicate with a communication network by transmitting wirelesssignals to, or receiving wireless signals from, a local transceiver 115over a wireless communication link 125.

In a particular implementation, a local transceiver 115 may bepositioned in an indoor environment. A local transceiver 115 may provideaccess to a wireless local area network (WLAN, e.g., IEEE Std. 802.11network) or wireless personal area network (WPAN, e.g., Bluetoothnetwork). In another example implementation, a local transceiver 115 maycomprise a femto cell transceiver capable of facilitating communicationon wireless communication link 125 according to a cellular communicationprotocol. Of course it should be understood that these are merelyexamples of networks that may communicate with a mobile device over awireless link, and claimed subject matter is not limited in thisrespect.

In a particular implementation, local transceiver 115 a or 115 b maycommunicate with servers 140, 150 and/or 155 over a network 130 throughlinks 145. Here, network 130 may comprise any combination of wired orwireless links. In a particular implementation, network 130 may compriseInternet Protocol (IP) infrastructure capable of facilitatingcommunication between a mobile device 100 and servers 140, 150 or 155through a local transceiver 115. In another implementation, network 130may comprise wired or wireless communication network infrastructure tofacilitate mobile cellular communication with mobile device 100.

In a particular implementation, mobile device 100 may be capable ofcomputing a position fix based, at least in part, on signals acquiredfrom local transmitters (e.g., WLAN access points positioned at knownlocations). For example, mobile devices may obtain a position fix bymeasuring ranges to three or more indoor terrestrial wireless accesspoints which are positioned at known locations. Such ranges may bemeasured, for example, by obtaining a MAC ID address from signalsreceived from such access points and obtaining range measurements to theaccess points by measuring one or more characteristics of signalsreceived from such access points such as, for example, received signalstrength (RSSI) or RTT.

In particular implementations, a mobile device 100 or a localtransceiver 115 may receive positioning assistance data for indoorpositioning operations from servers 140, 150 or 155. For example, suchpositioning assistance data may include locations and identities oftransmitters positioned at known locations to enable measuring ranges tothese transmitters based, at least in part, on a measured RSSI and/orRTT, for example.

In a particular implementation, particular messages flows betweenwireless STAs may be implemented for obtaining a measurement of RTT froman exchange of messages between the STAs for use in positioningoperations as discussed above. In particular implementations, asdescribed below, any STA may comprise a mobile device (e.g., mobiledevice 100) or a stationary transceiver (e.g., IEEE std. 802.11 accesspoint, stationary Bluetooth device, local transceiver 115, etc.). Assuch, an exchange of messages between wireless STAs may comprise anexchange of messages between a mobile device and a stationarytransceiver (e.g., between a mobile device 100 and local transceiver 115over a wireless link 125), between two peer mobile devices (e.g.,between mobile devices 100 a and 100 b over wireless link 159), orbetween two stationary transceivers (e.g., between local transceiver 115a and local transceiver 115 b over wireless link 179), just to provide afew examples. In particular implementations, various techniquesdescribed herein may incorporate some, but not necessarily all, aspectsor features of IEEE P802.11-REVmc™/D6.0 Draft Standard 802.11 forInformation technology—Telecommunications and information exchangebetween systems, Local and metropolitan area networks—Specificrequirements Part 11: Wireless LAN Medium Access Control (MAC) andPhysical Layer (PHY), January 2016, section 11.24.6 (hereinafter “IEEEstd. 802.11”). Indeed, it should be understood that some featuresdescribed herein are not shown, described or taught in the IEEE std.802.11.

FIG. 2 is a diagram illustrating a message flow between wirelessstations (STAs) including a “responding” STA and an “initiating” STAaccording to an embodiment. In this context, a STA, such as a respondingSTA or initiating STA, may comprise any one of several transceiverdevices including a mobile device (e.g., mobile device 100) orstationary access transceiver device (e.g., local transceiver 115).Particular features of a STA may be shown in example implementationsshown in FIGS. 9 and 10, for example. It should be understood, however,that these are merely examples of an initiating STA or a responding STA,and claimed subject matter is not limited in this respect. An initiatingSTA may obtain or compute one or more measurements of RTT based, atleast in part, on timing of messages or frames transmitted between theinitiating STA and a responding STA. As used herein, the terms “message”and “frame” are used interchangeably. The initiating STA may transmit afine timing measurement request message or frame (“Request”) 202 to theresponding STA and receive a fine timing request message acknowledgementmessage or frame (“Ack”) 204 transmitted in response. In a particularimplementation, while not limiting claimed subject matter in thisrespect, contents of such a fine timing measurement request message 202may be as shown in the IEEE std. 802.11. In particular implementations,such an Ack frame 204 may merely provide an indication of receipt of apreviously transmitted message. The initiating STA may then obtain orcompute an RTT measurement based, at least in part, on time stamp values(t1, t4) provided in fine timing measurement messages or frames (“M”)206 received from the responding STA (and transmitted in response toreceipt of a fine timing measurement request message). In a particularimplementation, as shown in the message flow diagram, a sequence ofmultiple exchanges of alternating fine timing measurement messages 206followed by fine timing measurement acknowledgement messages 208 maycreate additional time stamp values (t1, t2, t3 and t4).

According to an embodiment, a fine timing measurement request (FTMR)message transmitted by an initiating STA may include fields, parameters,etc. characterizing a desired exchange of messages with a responding STAto provide fine timing measurements to the initiating STA enabling theinitiating STA to compute an RTT measurement. In response to receipt ofa FTM request message, a responding STA may transmit to the initiatingSTA one or more fine timing measurement (FTM) messages includingmeasurements or parameters enabling the initiating STA to compute RTT orother parameters indicative of range.

In this context, an “FTM message” comprises a message transmitted from atransmitting device having one or more features that enables a devicereceiving the message to determine a time of receipt of the message. Ina particular implementation, while not limiting claimed subject matterin this respect, contents of such a fine timing measurement message orframe may be as shown in the IEEE std. 802.11 at section. In one exampleimplementation, an initiating STA may compute an RTT measurement as(t4−t1)−(t3−t2), where t2 and t3 are the time of receipt of a previousfine timing measurement message or frame and transmission of a precedingacknowledgement message or frame, respectively. The initiating STA mayreceive fine timing measurement frames in a burst to obtain acorresponding number of RTT measurements which may be combined for useof unbiased measurement noise in computing a range between theinitiating and responding STAs.

According to an embodiment, a TOF of a message wirelessly transmittedfrom a transmitting device and acquired at a receiving device may bemeasured if the transmitted message includes a time stamp valueindicating a transmission time. In a particular implementation, thetransmitted message may comprise fields (e.g., preamble, header andpayload) containing encoded symbols that are detectable at the receivingdevice. To acquire the transmitted message and determine a time ofarrival, the receiving device may detect or decode a particular symbolor symbols in a sequence of symbols being transmitted by the message. Ifthe particular symbol is referenced to the time stamp value alsoincluded in the transmitted message, the receiving device may measureTOF=RTT/2 based on a different between the time stamp value and aninstance that the particular symbol is decoded or detected.

As discussed above in connection with FIG. 2, an initiating STA maycompute an RTT measurement based, at least in part, on a time of arrival(t4) of an acknowledgment message transmitted by the initiating STAacknowledging receipt of an FTM message. In some scenarios, a roguedevice (i.e., other than the initiating STA) may snoop FTM messagestransmitted by a responding STA to the initiating STA, and transmitspoofed acknowledgement messages. This is illustrated by a non-limitingexample shown in FIG. 3, a snooping STA may intercept an initial FTMmessage 302 intended for initiating STA STA2 and transmit a spoofedacknowledgment message 304 arriving at responding STA STA1 at time t4′(arriving earlier than a time t4 of an authentic acknowledgement message306 transmitted from initiating STA STA2). Treating spoofedacknowledgement message 304 as an authentic acknowledgment message, STA1may transmit a subsequent FTM message 308 having a time of arrival T4′of the spoofed acknowledgement message. STA2 may then compute anerroneous RTT based on time of arrival T4′ of spoofed acknowledgementmessage 304. If the spoofing STA is closer to responding STA1 than isinitiating STA STA2, for example, a time of arrival T4′ may lead to asmaller value for RTT than if RTT is computed using a time of arrival T4of authentic acknowledgement message 306.

In one particular implementation, a responding STA may authenticatemessages received from an initiating STA acknowledging receipt of an FTMmessage based, at least in part, on one or more fields in the receivedmessage. FIG. 4A is a flow diagram of a process for determining whetheran acknowledgement message received at a responding STA is authentic. Atblock 402, a first STA may transmit an FTM message which is addressed toa second STA. In a particular example, an FTM message transmitted atblock 402 may comprise FTM message 302 transmitted from STA1 in responseto receipt of an FTM request message (not shown) which is transmittedfrom ST2. Accordingly, in a particular embodiment, an FTM messagetransmitted at block 402 may be addressed to a STA that transmitted anFTM request message initiating the FTM message. In particularimplementations, block 402 may be performed or enabled, at least inpart, by wireless transceiver 1121 and antenna 1123 (FIG. 9) orcommunication interface 1830 and antenna 1808 (FIG. 10).

At block 404, a STA may conditionally authenticate a received message asbeing transmitted by a wireless transceiver device acknowledging receiptof the FTM message transmitted at block 402. For example, as pointed outabove in FIG. 3, block 404 may attempt to determine whether message 304or message 306 is an authentic acknowledgement message transmitted bySTA2 in response to receipt of FTM message 302. In this context,“authentication” of a message as being transmitted by a particularwireless transceiver device is a process by which aspects orcharacteristics of the message are evaluated to infer whether themessage was indeed transmitted by the particular wireless transceiverdevice. If such a message is not authenticated, for example, a recipientdevice may compute TOF or FTT using information other than a time ofarrival of the unauthenticated message, for example, and/or may nottransmit the arrival time of the message in a subsequent FTM message(e.g., FTM message 308). This may, for example, prevent transmission ofan FTM message having an erroneous time of arrival T4 (e.g., preventstransmission of FTM message 308 having an erroneous T4′ value). Inparticular implementations, block 404 may be performed or enabled, atleast in part, by general purpose/application processor 1111 or DSP(s)1112 in combination with instructions stored on memory 1140 (FIG. 9) orby processing unit 1820 in combination with instructions stored onmemory 1822, for example.

FIG. 4B is an example process performed by an initiating STA incommunication with a responding STA processing acknowledgement messagesaccording to FIG. 4A. Block 452 may transmit an acknowledgement messageacknowledging receipt of a first FTM message transmitted by a respondingSTA. In an example, the acknowledgement message transmitted at block 452may be received by a responding STA according to block 402. Inparticular implementations, block 452 may be performed or enabled, atleast in part, by general purpose/application processor 1111 or DSP(s)1112 in combination with instructions stored on memory 1140 (FIG. 9) orby processing unit 1820 in combination with instructions stored onmemory 1822, for example.

Block 454 may involve receipt of a second FTM message transmitted from aresponding STA. Here, the second FTM message may comprise one or moreparameters based, at least in part, on a time of an authenticatedreceipt at the responding STA of the acknowledgement message transmittedat block 452. In this context, a “time of an authenticated receipt of anacknowledgement message” means a time of arrival of an acknowledgementmessage that has been authenticated as being transmitted from aparticular source device. For example, “a time of an authenticatedreceipt of an acknowledgement message” may comprise a time of receipt ofan acknowledgement message that has been authenticated according toblock 404 as discussed herein, for example. In particularimplementations, block 454 may be performed or enabled, at least inpart, by general purpose/application processor 1111 or DSP(s) 1112 incombination with instructions stored on memory 1140 (FIG. 9) or byprocessing unit 1820 in combination with instructions stored on memory1822, for example.

According to an embodiment, block 404 may conditionally authenticate anacknowledgement message based, at least in part, on contents of themessage such as a media access control (MAC) address in a header of theacknowledgment message. For example, block 404 may compare a MAC addressin a source field of a received message (e.g., message spoofedacknowledgement message 304 or acknowledgement message 306) with asource address in a field of a previous FTM message (e.g., FTM message302), and authenticate the received message if there is a match. In oneaspect, a header of an acknowledgement message may be modified tospecify not only a destination address of an intended recipient devicebut also a MAC address of a device transmitting the acknowledgmentmessage. As shown in FIG. 6, for example, the IEEE std. 802.11 specifiesthat a MAC header include an address for the acknowledgment message(e.g., a first tokenBSSID of an intended recipient responding STA) butdoes not specify that a MAC header include an address for a devicetransmitting the acknowledgment message. As shown in FIG. 5, accordingto an embodiment, additional fields may be included to specifyaddresses, wherein a field “Address 1” may specify a BSSID of adestination responding STA and a field “Address 2” may specify a BSSIDof a source initiating STA. Here, a responding STA receiving anacknowledgement message with field “Address 2” may authenticate theacknowledgment message (e.g., acknowledgement message 306) if a sourceBSSID of a transmitting device in field “Address 2” matches adestination field of a header in an FTM message (e.g., FTM message 302)previously transmitted by the responding STA.

In another embodiment, block 404 may conditionally authenticate anacknowledgement message by selecting an authentic acknowledgmentmessages from among multiple received messages. As shown in FIG. 7,responding STA STA1 may receive a spoofed acknowledgment message 706 atT4′ and receive an authentic acknowledgment message 708 (transmittedfrom initiating STA STA1 in response to FTM message 704) at a timeT4=T4′+Delta. Authentic acknowledgement message 708 may also include oneor more fields indicating T2 (indicating a time stamp of an arrival forpreceding FTM message 704) and T3 (indicating a time stamp oftransmission of authentic acknowledgment message 708 (or, alternatively,a value for T2-T3). Recognizing that T2−T1≈T4−T3, a recipient respondingSTA STA1 may then compare a time of arrival of a received message (e.g.,time of arrival of spoofed acknowledgement message 706 or time ofarrival of authentic acknowledgement message 708) with T3+(T2−T1) todetermine whether the acknowledgement message is authentic. If the timeof arrival of the acknowledgement message does not deviate significantlyfrom T3+(T2−T1) within an acceptable tolerance of error of the system, aresponding STA STA1 may authenticate the received message. Theresponding STA STA1 may then provide the time of arrival of theauthenticated received message in a subsequent FTM message 710 toinitiating STA STA2. On the other hand, if the time of arrival of thereceived message deviates significantly from T3+(T2−T1), responding STASTA1 may not provide the time of arrival of the received message as T4in subsequent FTM message 710 transmitted to initiating STA STA1. In analternative implementation, initiating STA STA1 may compute RTT based ontimes T2 and T3 (and without using T4).

According to an embodiment, an initiating STA may optionally initiatethe process of FIG. 4A in applications that are particularly vulnerableto erroneous time stamp values (e.g., T4′) in FTM messages transmittedfrom a responding STA. In a particular embodiment, as shown in FIG. 7,an initial FTMR message 702 transmitted by initiating STA STA2 mayinclude a parameter (e.g., a value of “3” in a “Trigger” field)specifying that messages acknowledging receipt of FTM messages are to beauthenticated at a recipient responding STA according to one or moreparticular embodiments of the process of FIG. 4A. It should beunderstood, however, that use of a particular value in a Trigger fieldof an FTM request message is merely an example of how an initiating STAmay indicate that acknowledgement messages are to be processed in asecure fashion, and claimed subject matter is not limited in thisrespect.

In an alternative embodiment shown in FIG. 8, a responding STA STA1 atblock 404 may conditionally authenticate received messages asacknowledgement messages based, at least in part, on an exchange oftokens between responding STA STA1 and an initiating STA STA2, and apredetermined function. To enable increased accuracy in detection oftime of arrival of acknowledgement messages at a responding STA, aninitiating STA may transmit acknowledgement messages in a signal withincreased frequency tones. In the particular implementation of FIG. 8,for example, initiating STA STA2 may increase frequency tones ofacknowledgement messages by transmitting the acknowledgement messages ina particular signaling format such as a HT/VHT/HE format. Initiating STASTA1 may include in FTM request messages and acknowledgement messagestokens such as in the form of a bit pattern in a particular messagefield. For example, in an FTMR message 802, initiating STA STA2 mayinclude a first token Token1. An initial FTM message 804 transmitted byresponding STA STA1 in response to FTMR message 802 may include a secondtoken Token2 (such as a second bit pattern in a particular field of FTMmessage 804). A subsequent acknowledgement message 810 from initiatingSTA STA2 acknowledging receipt of FTM message 804 may then include aToken3 computed as a particular function (e.g., a hash function) ofToken1 and Token2. On receipt of acknowledgement message 810acknowledging receipt of FTM message 804, responding STA STA1 mayauthenticate acknowledgement message 810 by computing the particularfunction of Token1 and Token2 to obtain a result, and comparing theresult with Token3 obtained from received FTM message 810. RespondingSTA STA1 may choose to ignore an Ack frame that does not have theexpected Token3 value.

According to an embodiment, a responding STA may individuallyauthenticate messages as acknowledgements of multiple FTM messagestransmitted in a burst of FTM messages requested by an FTM requestmessage. In the example message flow of FIG. 8, FTM messages 804 and 812may be transmitted in a burst of FTM messages requested by FTM requestmessage 802. Following transmission of FTM message 812 containing avalue of a time of receipt of authenticated acknowledgement message 810,responding STA STA1 of FIG. 8 may similarly authenticate a subsequentreceived message based on one or more different Tokens provided in thesubsequent received message. For example, responding STA STA1 mayreplace Token2 in FTM message 804 with Token4 in FTM message 812. Inresponse to receipt of FTM message 812, initiating STA STA2 may transmitacknowledgement message 814 containing Token5 as the result ofcomputation of the particular function based on Token1 and Token4(obtained from received FTM message 812). On receipt of acknowledgementmessage 814 acknowledging receipt of FTM message 812, responding STASTA1 may authenticate acknowledgement message 812 by computing theparticular function of Token1 and Token4 to obtain a result, andcomparing with Token5 obtained from received FTM message 814.

FIG. 9 is a schematic diagram of a mobile device according to anembodiment. Mobile device 100 (FIG. 1) may comprise one or more featuresof mobile device 1100 shown in FIG. 8. In certain embodiments, mobiledevice 1100 may also comprise a wireless transceiver 1121 which iscapable of transmitting and receiving wireless signals 1123 via wirelessantenna 1122 over a wireless communication network. Wireless transceiver1121 may be connected to bus 1101 by a wireless transceiver businterface 1120. Wireless transceiver bus interface 1120 may, in someembodiments be at least partially integrated with wireless transceiver1121. Some embodiments may include multiple wireless transceivers 1121and wireless antennas 1122 to enable transmitting and/or receivingsignals according to a corresponding multiple wireless communicationstandards such as, for example, versions of IEEE Std. 802.11, CDMA,WCDMA, LTE, UMTS, GSM, AMPS, Zigbee and Bluetooth, just to name a fewexamples. In an implementation, wireless transceiver 1121 may transmitor receive messages or frames (including components such as bits, bytes,values, parameters, fields, etc.) comprising signals in a physicaltransmission medium such as a physical transmission medium employed in acommunication network.

Mobile device 1100 may also comprise SPS receiver 1155 capable ofreceiving and acquiring SPS signals 1159 via SPS antenna 1158. SPSreceiver 1155 may also process, in whole or in part, acquired SPSsignals 1159 for estimating a location of mobile device 1100. In someembodiments, general-purpose processor(s) 1111, memory 1140, DSP(s) 1112and/or specialized processors (not shown) may also be utilized toprocess acquired SPS signals, in whole or in part, and/or calculate anestimated location of mobile device 1100, in conjunction with SPSreceiver 1155. Storage of SPS or other signals for use in performingpositioning operations may be performed in memory 1140 or registers (notshown).

Also shown in FIG. 9, mobile device 1100 may comprise digital signalprocessor(s) (DSP(s)) 1112 connected to the bus 1101 by a bus interface1110, general-purpose processor(s) 1111 connected to the bus 1101 by abus interface 1110 and memory 1140. Bus interface 1110 may be integratedwith the DSP(s) 1112, general-purpose processor(s) 1111 and memory 1140.In various embodiments, functions may be performed in response executionof one or more machine-readable instructions stored in memory 1140 suchas on a computer-readable storage medium, such as RAM, ROM, FLASH, ordisc drive, just to name a few example. The one or more instructions maybe executable by general-purpose processor(s) 1111, specializedprocessors, or DSP(s) 1112. Memory 1140 may comprise a non-transitoryprocessor-readable memory and/or a computer-readable memory that storessoftware code (programming code, instructions, etc.) that are executableby processor(s) 1111 and/or DSP(s) 1112 to perform functions describedherein. In a particular implementation, wireless transceiver 1121 maycommunicate with general-purpose processor(s) 1111 and/or DSP(s) 1112through bus 1101 to enable mobile device 1100 to be configured as awireless STA as discussed above. General-purpose processor(s) 1111and/or DSP(s) 1112 may execute instructions to execute one or moreaspects of processes discussed above in connection with FIGS. 2 through8.

Also shown in FIG. 9, a user interface 1135 may comprise any one ofseveral devices such as, for example, a speaker, microphone, displaydevice, vibration device, keyboard, touch screen, just to name a fewexamples. In a particular implementation, user interface 1135 may enablea user to interact with one or more applications hosted on mobile device1100. For example, devices of user interface 1135 may store analog ordigital signals on memory 1140 to be further processed by DSP(s) 1112 orgeneral purpose/application processor 1111 in response to action from auser. Similarly, applications hosted on mobile device 1100 may storeanalog or digital signals on memory 1140 to present an output signal toa user. In another implementation, mobile device 1100 may optionallyinclude a dedicated audio input/output (I/O) device 1170 comprising, forexample, a dedicated speaker, microphone, digital to analog circuitry,analog to digital circuitry, amplifiers and/or gain control. It shouldbe understood, however, that this is merely an example of how an audioI/O may be implemented in a mobile device, and that claimed subjectmatter is not limited in this respect. In another implementation, mobiledevice 1100 may comprise touch sensors 1162 responsive to touching orpressure on a keyboard or touch screen device.

Mobile device 1100 may also comprise a dedicated camera device 1164 forcapturing still or moving imagery. Dedicated camera device 1164 maycomprise, for example an imaging sensor (e.g., charge coupled device orCMOS imager), lens, analog to digital circuitry, frame buffers, just toname a few examples. In one implementation, additional processing,conditioning, encoding or compression of signals representing capturedimages may be performed at general purpose/application processor 1111 orDSP(s) 1112. Alternatively, a dedicated video processor 1168 may performconditioning, encoding, compression or manipulation of signalsrepresenting captured images. Additionally, dedicated video processor1168 may decode/decompress stored image data for presentation on adisplay device (not shown) on mobile device 1100.

Mobile device 1100 may also comprise sensors 1160 coupled to bus 1101which may include, for example, inertial sensors and environmentsensors. Inertial sensors of sensors 1160 may comprise, for exampleaccelerometers (e.g., collectively responding to acceleration of mobiledevice 1100 in three dimensions), one or more gyroscopes or one or moremagnetometers (e.g., to support one or more compass applications).Environment sensors of mobile device 1100 may comprise, for example,temperature sensors, barometric pressure sensors, ambient light sensors,camera imagers, microphones, just to name few examples. Sensors 1160 maygenerate analog or digital signals that may be stored in memory 1140 andprocessed by DPS(s) or general purpose/application processor 1111 insupport of one or more applications such as, for example, applicationsdirected to positioning or navigation operations.

In a particular implementation, mobile device 1100 may comprise adedicated modem processor 1166 capable of performing baseband processingof signals received and downconverted at wireless transceiver 1121 orSPS receiver 1155. Similarly, dedicated modem processor 1166 may performbaseband processing of signals to be upconverted for transmission bywireless transceiver 1121. In alternative implementations, instead ofhaving a dedicated modem processor, baseband processing may be performedby a general purpose processor or DSP (e.g., general purpose/applicationprocessor 1111 or DSP(s) 1112). It should be understood, however, thatthese are merely examples of structures that may perform basebandprocessing, and that claimed subject matter is not limited in thisrespect.

FIG. 10 is a schematic diagram illustrating an example system 1800 thatmay include one or more devices configurable to implement techniques orprocesses described above, for example, in connection with FIG. 1.System 1800 may include, for example, a first device 1802, a seconddevice 1804, and a third device 1806, which may be operatively coupledtogether through a wireless communications network. In an aspect, firstdevice 1802 may comprise an access point as shown, for example. Seconddevice 1804 may comprise an access point (e.g., local transceiver 115 orbase station transceiver 110) and third device 1806 may comprise amobile station or mobile device, in an aspect. Also, in an aspect,devices 1802, 1804 and 1802 may be included in a wireless communicationsnetwork may comprise one or more wireless access points, for example.However, claimed subject matter is not limited in scope in theserespects.

First device 1802, second device 1804 and third device 1806, as shown inFIG. 10, may be representative of any device, appliance or machine thatmay be configurable to exchange data over a wireless communicationsnetwork. By way of example but not limitation, any of first device 1802,second device 1804, or third device 1806 may include: one or morecomputing devices or platforms, such as, e.g., a desktop computer, alaptop computer, a workstation, a server device, or the like; one ormore personal computing or communication devices or appliances, such as,e.g., a personal digital assistant, mobile communication device, or thelike; a computing system or associated service provider capability, suchas, e.g., a database or data storage service provider/system, a networkservice provider/system, an Internet or intranet serviceprovider/system, a portal or search engine service provider/system, awireless communication service provider/system; or any combinationthereof. Any of the first, second, and third devices 1802, 1804, and1806, respectively, may comprise one or more of an access point or amobile device in accordance with the examples described herein.

Similarly, a wireless communications network, as shown in FIG. 10, isrepresentative of one or more communication links, processes, orresources configurable to support the exchange of data between at leasttwo of first device 1802, second device 1804, and third device 1806. Byway of example but not limitation, a wireless communications network mayinclude wireless or wired communication links, telephone ortelecommunications systems, data buses or channels, optical fibers,terrestrial or space vehicle resources, local area networks, wide areanetworks, intranets, the Internet, routers or switches, and the like, orany combination thereof. As illustrated, for example, by the dashedlined box illustrated as being partially obscured of third device 1806,there may be additional like devices operatively coupled to wirelesscommunications network 1808.

It is recognized that all or part of the various devices and networksshown in FIG. 10, and the processes and methods as further describedherein, may be implemented using or otherwise including hardware,firmware, software, or any combination thereof.

Thus, by way of example but not limitation, second device 1804 mayinclude at least one processing unit 1820 that is operatively coupled toa memory 1822 through a bus 1828.

Processing unit 1820 is representative of one or more circuitsconfigurable to perform at least a portion of a data computing procedureor process. By way of example but not limitation, processing unit 1820may include one or more processors, controllers, microprocessors,microcontrollers, application specific integrated circuits, digitalsignal processors, programmable logic devices, field programmable gatearrays, and the like, or any combination thereof.

Memory 1822 is representative of any data storage mechanism. Memory 1822may include, for example, a primary memory 1824 or a secondary memory1826. Primary memory 1824 may include, for example, a random accessmemory, read only memory, etc. While illustrated in this example asbeing separate from processing unit 1820, it should be understood thatall or part of primary memory 1824 may be provided within or otherwiseco-located/coupled with processing unit 1820. In a particularimplementation, memory 1822 and processing unit 1820 may be configuredto execute one or more aspects of process discussed above in connectionwith FIGS. 2 through 8.

Secondary memory 1826 may include, for example, the same or similar typeof memory as primary memory or one or more data storage devices orsystems, such as, for example, a disk drive, an optical disc drive, atape drive, a solid state memory drive, etc. In certain implementations,secondary memory 1826 may be operatively receptive of, or otherwiseconfigurable to couple to, a computer-readable medium 1840.Computer-readable medium 1840 may include, for example, anynon-transitory medium that can carry or make accessible data, code orinstructions for one or more of the devices in system 1800.Computer-readable medium 1840 may also be referred to as a storagemedium.

Second device 1804 may include, for example, a communication interface1830 that provides for or otherwise supports the operative coupling ofsecond device 1804 to a wireless communications network at least throughan antenna 1808. By way of example but not limitation, communicationinterface 1830 may include a network interface device or card, a modem,a router, a switch, a transceiver device, and the like. In otheralternative implementations, communication interface 1830 may comprise awired/LAN interface, wireless LAN interface (e.g., IEEE std. 802.11wireless interface) and/or a wide area network (WAN) air interface. Inan implementation, communication interface 1830 may transmit or receivemessages or frames (including components such as bits, bytes, values,parameters, fields, etc.) comprising signals in a physical transmissionmedium such as a physical transmission medium employed in acommunication network.

In a particular implementation, antenna 1808 in combination withcommunication interface 1830 may be used to implement transmission andreception of signals as illustrated in FIGS. 2 through 8.

In one particular implementation, transmission of an ACK message inresponse to a FTM measurement request message may be performed atcommunication interface 1830 without instruction or initiation fromprocessing unit 1830.

Second device 1804 may include, for example, an input/output device1832. Input/output device 1832 is representative of one or more devicesor features that may be configurable to accept or otherwise introducehuman or machine inputs, or one or more devices or features that may beconfigurable to deliver or otherwise provide for human or machineoutputs. By way of example but not limitation, input/output device 1832may include an operatively configured display, speaker, keyboard, mouse,trackball, touch screen, data port, etc.

In a particular embodiment a method at a first wireless transceiverdevice comprises: transmitting a first acknowledgement messageindicating receipt of a first fine timing measurement (FTM) messagetransmitted by a second wireless transceiver device; and receiving asecond FTM message from the second wireless transceiver, the second FTMmessage comprising one or more parameters based, at least in part, on atime of an authenticated receipt of the first acknowledgement message atthe second wireless transceiver device. In a particular implementation,the method further comprises transmitting an FTM request messagecomprising one or more parameters requesting that the second wirelesstransceiver device authenticate messages acknowledging receipt of atleast the first FTM message. For example, the one or more parametersrequesting that the second wireless transceiver device authenticatemessages acknowledging receipt of at least the first FTM messagecomprise one or more values in a Trigger field of the FTM requestmessage. In another implementation, the first FTM message is transmittedby the second wireless transceiver device in response to receipt of anFTM request message comprising a first token, the FTM request messagebeing transmitted from the first wireless transceiver device, whereinthe first FTM message comprises a second token and the firstacknowledgement message comprises a third token, and the method furthercomprises: receiving a second FTM message transmitted from the secondwireless transceiver device, the second FTM message comprising one ormore parameters based, at least in part, on a time of authenticatedreceipt of the second acknowledgement message at the second wirelesstransceiver device, the second acknowledgement message beingauthenticated at the second wireless transceiver device based, at leastin part, on a comparison of the third token to a value computed at thesecond wireless transceiver device as a function of the first token andthe second token. In another implementation, wherein the second FTMmessage comprises a fourth token, the method further comprising:transmitting a second acknowledgement message indicating receipt of thesecond FTM message transmitted by the second wireless transceiverdevice, the second acknowledgement message comprising a fifth token; andreceiving a third FTM message transmitted from the second wirelesstransceiver device comprising one or more parameters based, at least inpart, on a time of authenticated receipt of the second acknowledgementmessage at the second wireless transceiver device, the secondacknowledgement message being authenticated at the second wirelesstransceiver device based, at least in part, on a comparison of the fifthtoken to a value computed as a function of the first token and thefourth token. In another particular implementation, the firstacknowledgement message comprises one or more parameters indicating atime of arrival of the first FTM message at the first wirelesstransceiver device and a time that the first acknowledgement message istransmitted from the first wireless transceiver device, and wherein thefirst acknowledgement message is authenticated at the second wirelesstransceiver device as being transmitted by the first wirelesstransceiver device based, at least in part, on a comparison of a time ofarrival of the first acknowledgement message with a value based, atleast in part, on the one or more parameters indicating the time thatthe first FTM message is received at the second wireless transceiverdevice and the time that the first acknowledgement message istransmitted from the second wireless transceiver device.

In another embodiment, a first wireless station (STA) comprises: awireless transceiver to transmit messages to and received messages froma communication network; and a processor coupled to the wirelesstransceiver, the processor being configured to: initiate transmission ofa first acknowledgement message through the wireless transceiverindicating receipt of a first fine timing measurement (FTM) messagetransmitted by a second STA and received at the wireless transceiver;and obtain a second FTM message received at the wireless transceiverfrom the second STA, the second FTM message comprising one or moreparameters based, at least in part, on a time of an authenticatedreceipt of the first acknowledgement message at the second STA. In aparticular implementation, the one or more processors are furtherconfigured to initiate transmission of an FTM request message comprisingone or more parameters requesting that the second STA authenticatemessages acknowledging receipt of at least the first FTM message. Inanother particular implementation, the one or more parameters requestingthat the second STA authenticate messages acknowledging receipt of atleast the first FTM message comprise one or more values in a Triggerfield of the FTM request message. In another particular implementation,the first FTM message is transmitted by the second STA in response toreceipt of an FTM request message comprising a first token, the FTMrequest message being transmitted from the first STA, wherein the firstFTM message comprises a second token and the first acknowledgementmessage comprises a third token, and wherein the processor is furtherconfigured to: obtain a second FTM message received at the wirelesstransceiver and transmitted from the second STA, the second FTM messagecomprising one or more parameters based, at least in part, on a time ofauthenticated receipt of the second acknowledgement message at thesecond STA, the second acknowledgement message being authenticated atthe second STA based, at least in part, on a comparison of the thirdtoken to a value computed at the second STA as a function of the firsttoken and the second token. In another particular implementation, thesecond FTM message comprises a fourth token, and wherein the processoris further configured to: initiate transmission of a secondacknowledgement message through the wireless transceiver indicatingreceipt of the second FTM message transmitted by the second STA, thesecond acknowledgement message comprising a fifth token; and obtain athird FTM message received at the wireless transmitter and transmittedfrom the second STA comprising one or more parameters based, at least inpart, on a time of authenticated receipt of the second acknowledgementmessage at the second STA, the second acknowledgement message beingauthenticated at the second STA based, at least in part, on a comparisonof the fifth token to a value computed as a function of the first tokenand the fourth token. In another particular implementation, the firstacknowledgement message comprises one or more parameters indicating atime of arrival of the first FTM message at the first STA and a timethat the first acknowledgement message is transmitted from the firstSTA, and wherein the first acknowledgement message is authenticated atthe second STA as being transmitted by the first STA based, at least inpart, on a comparison of a time of arrival of the first acknowledgementmessage with a value based, at least in part, on the one or moreparameters indicating the time that the first FTM message is received atthe second STA and the time that the first acknowledgement message istransmitted from the second STA.

In another embodiment, a non-transitory storage medium comprisescomputer readable instructions stored thereon which are executable by aprocessor of a first wireless transceiver device to: initiatetransmission of a first acknowledgement message indicating receipt, atthe first wireless transceiver device, of a first fine timingmeasurement (FTM) message transmitted by a second wireless transceiverdevice; and obtain a second FTM message received at the first wirelesstransceiver device from the second wireless transceiver, the second FTMmessage comprising one or more parameters based, at least in part, on atime of an authenticated receipt of the first acknowledgement message atthe second wireless transceiver device. In a particular implementation,the instructions are further executable by the processor to: initiatetransmission of an FTM request message comprising one or more parametersrequesting that the second wireless transceiver device authenticatemessages acknowledging receipt of at least the first FTM message. Inanother particular implementation, the one or more parameters requestingthat the second wireless transceiver device authenticate messagesacknowledging receipt of at least the first FTM message comprise one ormore values in a Trigger field of the FTM request message. In anotherparticular implementation, the first FTM message is transmitted by thesecond wireless transceiver device in response to receipt of an FTMrequest message comprising a first token, the FTM request message beingtransmitted from the first wireless transceiver device, wherein thefirst FTM message comprises a second token and the first acknowledgementmessage comprises a third token, and wherein the instructions arefurther executable by the processor to: obtain a second FTM messagereceived at the first wireless transceiver device and transmitted fromthe second wireless transceiver device, the second FTM messagecomprising one or more parameters based, at least in part, on a time ofauthenticated receipt of the second acknowledgement message at thesecond wireless transceiver device, the second acknowledgement messagebeing authenticated at the second wireless transceiver device based, atleast in part, on a comparison of the third token to a value computed atthe second wireless transceiver device as a function of the first tokenand the second token. For example, the second FTM message may comprise afourth token, and wherein the instructions are further executable by theprocessor to: initiate transmission of a second acknowledgement messageindicating receipt of the second FTM message transmitted by the secondwireless transceiver device, the second acknowledgement messagecomprising a fifth token; and obtain a third FTM message received at thefirst wireless transceiver device and transmitted from the secondwireless transceiver device comprising one or more parameters based, atleast in part, on a time of authenticated receipt of the secondacknowledgement message at the second wireless transceiver device, thesecond acknowledgement message being authenticated at the secondwireless transceiver device based, at least in part, on a comparison ofthe fifth token to a value computed as a function of the first token andthe fourth token. In another particular implementation, the firstacknowledgement message comprises one or more parameters indicating atime of arrival of the first FTM message at the first wirelesstransceiver device and a time that the first acknowledgement message istransmitted from the first wireless transceiver device, and wherein thefirst acknowledgement message is authenticated at the second wirelesstransceiver device as being transmitted by the first wirelesstransceiver device based, at least in part, on a comparison of a time ofarrival of the first acknowledgement message with a value based, atleast in part, on the one or more parameters indicating the time thatthe first FTM message is received at the second wireless transceiverdevice and the time that the first acknowledgement message istransmitted from the second wireless transceiver device.

In another embodiment, a first wireless transceiver device comprises:means for transmitting a first acknowledgement message indicatingreceipt of a first fine timing measurement (FTM) message transmitted bya second wireless transceiver device; and means for receiving a secondFTM message from the second wireless transceiver, the second FTM messagecomprising one or more parameters based, at least in part, on a time ofan authenticated receipt of the first acknowledgement message at thesecond wireless transceiver device. In one implementation, the firstwireless transceiver device further comprises means for transmitting anFTM request message comprising one or more parameters requesting thatthe second wireless transceiver device authenticate messagesacknowledging receipt of at least the first FTM message. In anotherimplementation, the one or more parameters requesting that the secondwireless transceiver device authenticate messages acknowledging receiptof at least the first FTM message comprise one or more values in aTrigger field of the FTM request message. In another particularimplementation, the first FTM message is transmitted by the secondwireless transceiver device in response to receipt of an FTM requestmessage comprising a first token, the FTM request message beingtransmitted from the first wireless transceiver device, wherein thefirst FTM message comprises a second token and the first acknowledgementmessage comprises a third token, and further comprising: means forreceiving a second FTM message transmitted from the second wirelesstransceiver device, the second FTM message comprising one or moreparameters based, at least in part, on a time of authenticated receiptof the second acknowledgement message at the second wireless transceiverdevice, the second acknowledgement message being authenticated at thesecond wireless transceiver device based, at least in part, on acomparison of the third token to a value computed at the second wirelesstransceiver device as a function of the first token and the secondtoken. In another implementation, the second FTM message comprises afourth token, the first wireless transceiver device further comprises:means for transmitting a second acknowledgement message indicatingreceipt of the second FTM message transmitted by the second wirelesstransceiver device, the second acknowledgement message comprising afifth token; and means for receiving a third FTM message transmittedfrom the second wireless transceiver device comprising one or moreparameters based, at least in part, on a time of authenticated receiptof the second acknowledgement message at the second wireless transceiverdevice, the second acknowledgement message being authenticated at thesecond wireless transceiver device based, at least in part, on acomparison of the fifth token to a value computed as a function of thefirst token and the fourth token. In a particular implementation, thefirst acknowledgement message comprises one or more parametersindicating a time of arrival of the first FTM message at the firstwireless transceiver device and a time that the first acknowledgementmessage is transmitted from the first wireless transceiver device, andwherein the first acknowledgement message is authenticated at the secondwireless transceiver device as being transmitted by the first wirelesstransceiver device based, at least in part, on a comparison of a time ofarrival of the first acknowledgement message with a value based, atleast in part, on the one or more parameters indicating the time thatthe first FTM message is received at the second wireless transceiverdevice and the time that the first acknowledgement message istransmitted from the second wireless transceiver device.

As used herein, the term “access point” is meant to include any wirelesscommunication station and/or device used to facilitate communication ina wireless communications system, such as, for example, a wireless localarea network, although the scope of claimed subject matter is notlimited in this respect. In another aspect, an access point may comprisea wireless local area network (WLAN) access point, for example. Such aWLAN may comprise a network compatible and/or compliant with one or moreversions of IEEE standard 802.11 in an aspect, although the scope ofclaimed subject matter is not limited in this respect. A WLAN accesspoint may provide communication between one or more mobile devices and anetwork such as the Internet, for example.

As used herein, the term “mobile device” refers to a device that mayfrom time to time have a position location that changes. The changes inposition location may comprise changes to direction, distance,orientation, etc., as a few examples. In particular examples, a mobiledevice may comprise a cellular telephone, wireless communication device,user equipment, laptop computer, other personal communication system(PCS) device, personal digital assistant (PDA), personal audio device(PAD), portable navigational device, and/or other portable communicationdevices. A mobile device may also comprise a processor and/or computingplatform adapted to perform functions controlled by machine-readableinstructions.

The methodologies described herein may be implemented by various meansdepending upon applications according to particular examples. Forexample, such methodologies may be implemented in hardware, firmware,software, or combinations thereof. In a hardware implementation, forexample, a processing unit may be implemented within one or moreapplication specific integrated circuits (“ASICs”), digital signalprocessors (“DSPs”), digital signal processing devices (“DSPDs”),programmable logic devices (“PLDs”), field programmable gate arrays(“FPGAs”), processors, controllers, micro-controllers, microprocessors,electronic devices, other devices units designed to perform thefunctions described herein, or combinations thereof.

Algorithmic descriptions and/or symbolic representations are examples oftechniques used by those of ordinary skill in the signal processingand/or related arts to convey the substance of their work to othersskilled in the art. An algorithm is here, and generally, is consideredto be a self-consistent sequence of operations and/or similar signalprocessing leading to a desired result. In this context, operationsand/or processing involve physical manipulation of physical quantities.Typically, although not necessarily, such quantities may take the formof electrical and/or magnetic signals and/or states capable of beingstored, transferred, combined, compared, processed or otherwisemanipulated as electronic signals and/or states representing variousforms of content, such as signal measurements, text, images, video,audio, etc. It has proven convenient at times, principally for reasonsof common usage, to refer to such physical signals and/or physicalstates as bits, bytes, values, elements, symbols, characters, terms,numbers, numerals, expressions, messages, fields, identifiers frames,measurements, content and/or the like. It should be understood, however,that all of these and/or similar terms are to be associated withappropriate physical quantities and are merely convenient labels. Unlessspecifically stated otherwise, as apparent from the precedingdiscussion, it is appreciated that throughout this specificationdiscussions utilizing terms such as “processing,” “computing,”“calculating,” “determining”, “establishing”, “obtaining”,“identifying”, “selecting”, “generating”, and/or the like may refer toactions and/or processes of a specific apparatus, such as a specialpurpose computer and/or a similar special purpose computing and/ornetwork device. In the context of this specification, therefore, aspecial purpose computer and/or a similar special purpose computingand/or network device is capable of processing, manipulating and/ortransforming signals and/or states, typically represented as physicalelectronic and/or magnetic quantities within memories, registers, and/orother storage devices, transmission devices, and/or display devices ofthe special purpose computer and/or similar special purpose computingand/or network device. In the context of this particular patentapplication, as mentioned, the term “specific apparatus” may include ageneral purpose computing and/or network device, such as a generalpurpose computer, once it is programmed to perform particular functionspursuant to instructions from program software.

In some circumstances, operation of a memory device, such as a change instate from a binary one to a binary zero or vice-versa, for example, maycomprise a transformation, such as a physical transformation. Withparticular types of memory devices, such a physical transformation maycomprise a physical transformation of an article to a different state orthing. For example, but without limitation, for some types of memorydevices, a change in state may involve an accumulation and/or storage ofcharge or a release of stored charge. Likewise, in other memory devices,a change of state may comprise a physical change, such as atransformation in magnetic orientation and/or a physical change and/ortransformation in molecular structure, such as from crystalline toamorphous or vice-versa. In still other memory devices, a change inphysical state may involve quantum mechanical phenomena, such as,superposition, entanglement, and/or the like, which may involve quantumbits (qubits), for example. The foregoing is not intended to be anexhaustive list of all examples in which a change in state form a binaryone to a binary zero or vice-versa in a memory device may comprise atransformation, such as a physical transformation. Rather, the foregoingis intended as illustrative examples.

Wireless communication techniques described herein may be in connectionwith various wireless communications networks such as a wireless widearea network (“WWAN”), a wireless local area network (“WLAN”), awireless personal area network (WPAN), and so on. In this context, a“wireless communication network” comprises multiple devices or nodescapable of communicating with one another through one or more wirelesscommunication links. As shown in FIG. 1, for example, a wirelesscommunication network may comprise two or more devices from mobiledevices 100 a, 100 b, 115 a and 115 b. The term “network” and “system”may be used interchangeably herein. A WWAN may be a Code DivisionMultiple Access (“CDMA”) network, a Time Division Multiple Access(“TDMA”) network, a Frequency Division Multiple Access (“FDMA”) network,an Orthogonal Frequency Division Multiple Access (“OFDMA”) network, aSingle-Carrier Frequency Division Multiple Access (“SC-FDMA”) network,or any combination of the above networks, and so on. A CDMA network mayimplement one or more radio access technologies (“RATs”) such ascdma2000, Wideband-CDMA (“W-CDMA”), to name just a few radiotechnologies. Here, cdma2000 may include technologies implementedaccording to IS-95, IS-2000, and IS-856 standards. A TDMA network mayimplement Global System for Mobile Communications (“GSM”), DigitalAdvanced Mobile Phone System (“D-AMPS”), or some other RAT. GSM andW-CDMA are described in documents from a consortium named “3rdGeneration Partnership Project” (“3GPP”). Cdma2000 is described indocuments from a consortium named “3rd Generation Partnership Project 2”(“3GPP2”). 3GPP and 3GPP2 documents are publicly available. 4G Long TermEvolution (“LTE”) communications networks may also be implemented inaccordance with claimed subject matter, in an aspect. A WLAN maycomprise an IEEE 802.11x network, and a WPAN may comprise a Bluetoothnetwork, an IEEE 802.15x, for example. Wireless communicationimplementations described herein may also be used in connection with anycombination of WWAN, WLAN or WPAN.

In another aspect, as previously mentioned, a wireless transmitter oraccess point may comprise a femtocell, utilized to extend cellulartelephone service into a business or home. In such an implementation,one or more mobile devices may communicate with a femtocell via a codedivision multiple access (“CDMA”) cellular communication protocol, forexample, and the femtocell may provide the mobile device access to alarger cellular telecommunication network by way of another broadbandnetwork such as the Internet.

Techniques described herein may be used with an SPS that includes anyone of several GNSS and/or combinations of GNSS. Furthermore, suchtechniques may be used with positioning systems that utilize terrestrialtransmitters acting as “pseudolites”, or a combination of SVs and suchterrestrial transmitters. Terrestrial transmitters may, for example,include ground-based transmitters that broadcast a PN code or otherranging code (e.g., similar to a GPS or CDMA cellular signal). Such atransmitter may be assigned a unique PN code so as to permitidentification by a remote receiver. Terrestrial transmitters may beuseful, for example, to augment an SPS in situations where SPS signalsfrom an orbiting SV might be unavailable, such as in tunnels, mines,buildings, urban canyons or other enclosed areas. Another implementationof pseudolites is known as radio-beacons. The term “SV”, as used herein,is intended to include terrestrial transmitters acting as pseudolites,equivalents of pseudolites, and possibly others. The terms “SPS signals”and/or “SV signals”, as used herein, is intended to include SPS-likesignals from terrestrial transmitters, including terrestrialtransmitters acting as pseudolites or equivalents of pseudolites.

Likewise, in this context, the terms “coupled”, “connected,” and/orsimilar terms are used generically. It should be understood that theseterms are not intended as synonyms. Rather, “connected” is usedgenerically to indicate that two or more components, for example, are indirect physical, including electrical, contact; while, “coupled” is usedgenerically to mean that two or more components are potentially indirect physical, including electrical, contact; however, “coupled” isalso used generically to also mean that two or more components are notnecessarily in direct contact, but nonetheless are able to co-operateand/or interact. The term coupled is also understood generically to meanindirectly connected, for example, in an appropriate context.

The terms, “and”, “or”, “and/or” and/or similar terms, as used herein,include a variety of meanings that also are expected to depend at leastin part upon the particular context in which such terms are used.Typically, “or” if used to associate a list, such as A, B or C, isintended to mean A, B, and C, here used in the inclusive sense, as wellas A, B or C, here used in the exclusive sense. In addition, the term“one or more” and/or similar terms is used to describe any feature,structure, and/or characteristic in the singular and/or is also used todescribe a plurality and/or some other combination of features,structures and/or characteristics. Likewise, the term “based on” and/orsimilar terms are understood as not necessarily intending to convey anexclusive set of factors, but to allow for existence of additionalfactors not necessarily expressly described. Of course, for all of theforegoing, particular context of description and/or usage provideshelpful guidance regarding inferences to be drawn. It should be notedthat the following description merely provides one or more illustrativeexamples and claimed subject matter is not limited to these one or moreexamples; however, again, particular context of description and/or usageprovides helpful guidance regarding inferences to be drawn.

In this context, the term network device refers to any device capable ofcommunicating via and/or as part of a network and may comprise acomputing device. While network devices may be capable of sending and/orreceiving signals (e.g., signal packets and/or frames), such as via awired and/or wireless network, they may also be capable of performingarithmetic and/or logic operations, processing and/or storing signals,such as in memory as physical memory states, and/or may, for example,operate as a server in various embodiments. Network devices capable ofoperating as a server, or otherwise, may include, as examples, dedicatedrack-mounted servers, desktop computers, laptop computers, set topboxes, tablets, netbooks, smart phones, wearable devices, integrateddevices combining two or more features of the foregoing devices, thelike or any combination thereof. Signal packets and/or frames, forexample, may be exchanged, such as between a server and a client deviceand/or other types of network devices, including between wirelessdevices coupled via a wireless network, for example. It is noted thatthe terms, server, server device, server computing device, servercomputing platform and/or similar terms are used interchangeably.Similarly, the terms client, client device, client computing device,client computing platform and/or similar terms are also usedinterchangeably. While in some instances, for ease of description, theseterms may be used in the singular, such as by referring to a “clientdevice” or a “server device,” the description is intended to encompassone or more client devices and/or one or more server devices, asappropriate. Along similar lines, references to a “database” areunderstood to mean, one or more databases and/or portions thereof, asappropriate.

It should be understood that for ease of description a network device(also referred to as a networking device) may be embodied and/ordescribed in terms of a computing device. However, it should further beunderstood that this description should in no way be construed thatclaimed subject matter is limited to one embodiment, such as a computingdevice and/or a network device, and, instead, may be embodied as avariety of devices or combinations thereof, including, for example, oneor more illustrative examples. References throughout this specificationto one implementation, an implementation, one embodiment, an embodimentand/or the like means that a particular feature, structure, and/orcharacteristic described in connection with a particular implementationand/or embodiment is included in at least one implementation and/orembodiment of claimed subject matter. Thus, appearances of such phrases,for example, in various places throughout this specification are notnecessarily intended to refer to the same implementation or to any oneparticular implementation described. Furthermore, it is to be understoodthat particular features, structures, and/or characteristics describedare capable of being combined in various ways in one or moreimplementations and, therefore, are within intended claim scope, forexample. In general, of course, these and other issues vary withcontext. Therefore, particular context of description and/or usageprovides helpful guidance regarding inferences to be drawn. While therehas been illustrated and described what are presently considered to beexample features, it will be understood by those skilled in the art thatvarious other modifications may be made, and equivalents may besubstituted, without departing from claimed subject matter.Additionally, many modifications may be made to adapt a particularsituation to the teachings of claimed subject matter without departingfrom the central concept described herein. Therefore, it is intendedthat claimed subject matter not be limited to the particular examplesdisclosed, but that such claimed subject matter may also include allaspects falling within the scope of the appended claims, and equivalentsthereof.

What is claimed is:
 1. At a first wireless transceiver device, a methodcomprising: transmitting a first fine timing measurement (FTM) messageaddressed to a second wireless transceiver device; and conditionallyauthenticating a received message as being transmitted by the secondwireless transceiver device and acknowledging receipt of the first FTMmessage.
 2. The method of claim 1, and further comprising: transmittinga second FTM message addressed to the second wireless transceiver devicecomprising one or more parameters indicating a time of arrival of thereceived message in response to authenticating the received message asbeing transmitted by the second wireless transceiver device andacknowledging receipt of the first FTM message.
 3. The method of claim1, wherein conditionally authenticating the received message as beingtransmitted by the second wireless transceiver device and acknowledgingreceipt of the first FTM message comprises authenticating the receivedmessage based, at least in part, on one or more parameters in thereceived message indicating a source device.
 4. The method of claim 3,wherein the one or more parameters are indicative of a BSSID of thesecond wireless transceiver device.
 5. The method of claim 1, whereinthe received message comprises one or more parameters indicating a timethat the first FTM message is received at the second wirelesstransceiver device and a time that the received message is transmittedfrom the second wireless transceiver device, and wherein conditionallyauthenticating the received message as being transmitted by the secondwireless transceiver device and acknowledging receipt of the first FTMmessage further comprises comparing a time of arrival of the receivedmessage with a value based, at least in part, on the one or moreparameters indicating the time that the first FTM message is received atthe second wireless transceiver device and the time that the receivedmessage is transmitted from the second wireless transceiver device. 6.The method of claim 1, wherein the first FTM message is transmitted inresponse to receipt of an FTM request message from the second wirelesstransceiver device comprising a first token, wherein the first FTMmessage comprises a second token and the received message comprises athird token, and wherein conditionally authenticating the receivedmessage as being transmitted by the second wireless transceiver deviceand acknowledging receipt of the first FTM message further comprisescomparing the third token to a value computed as a function of the firsttoken and the second token.
 7. The method of claim 6, and furthercomprising: transmitting a second FTM message addressed to the secondwireless transceiver device, the second FTM message comprising a fourthtoken; and conditionally authenticating receipt of a second receivedmessage, the second received message comprising a fifth token, as beingtransmitted by the second wireless transceiver device and acknowledgingreceipt of the second FTM message based, at least in part, on acomparison of the fifth token to a value computed as a function of thefirst token and the fourth token.
 8. The method of claim 1, wherein thefirst FTM message is transmitted in response to receipt of an FTMrequest message transmitted from the second wireless transceiver device,and wherein the FTM request message comprises a value in a “Trigger”field specifying authentication of messages acknowledging receipt of FTMmessages.
 9. A first wireless station (STA), comprising: a wirelesstransceiver to transmit messages to and receive messages from acommunication network; and a processor coupled to the wirelesstransceiver, the processor being configured to: initiate transmission ofa first fine timing measurement (FTM) message through the wirelesstransceiver, the first FTM message being addressed to a second STA; andconditionally authenticate a message received at the wirelesstransceiver as being transmitted by the second STA and acknowledgingreceipt of the first FTM message.
 10. The first STA of claim 9, whereinthe processor is further configured to: initiate transmission of asecond FTM message through the wireless transceiver addressed to thesecond STA comprising one or more parameters indicating a time ofarrival of the message received at the wireless transceiver in responseto authenticating the message received at the wireless transceiver asbeing transmitted by the second STA and acknowledging receipt of thefirst FTM message.
 11. The first STA of claim 9, wherein the processoris further configured to conditionally authenticate the message receivedat the wireless transceiver as being transmitted by the second STA andacknowledging receipt of the first FTM message by authenticating themessage received at the wireless transceiver based, at least in part, onone or more parameters in the message received at the wirelesstransceiver indicating a source device.
 12. The first STA of claim 11,wherein the one or more parameters are indicative of a BSSID of thesecond STA.
 13. The first STA of claim 9, wherein the message receivedat the wireless transceiver comprises one or more parameters indicatinga time that the first FTM message is received at the second STA and atime that the message received at the wireless transceiver istransmitted from the second STA, and wherein the processor is furtherconfigured to conditionally authenticate the message received at thewireless transceiver as being transmitted by the second STA andacknowledging receipt of the first FTM message by comparing a time ofarrival of the message at the wireless transceiver with a value based,at least in part, on the one or more parameters indicating the time thatthe first FTM message is received at the second STA and the time thatthe message received at the wireless transceiver is transmitted from thesecond STA.
 14. The first STA of claim 9, wherein the first FTM messageis transmitted in response to receipt of an FTM request message from thesecond STA comprising a first token, the first FTM message comprises asecond token and the message received at the wireless transceivercomprises a third token, and wherein the processor is further configuredto conditionally authenticate the message received at the wirelesstransceiver as being transmitted by the second STA and acknowledgingreceipt of the first FTM message by comparing the third token to a valuecomputed as a function of the first token and the second token.
 15. Thefirst STA of claim 14, wherein the processor is further configured to:initiate transmission of a second FTM message addressed to the secondSTA, the second FTM message comprising a fourth token; and conditionallyauthenticate receipt of a second received message, the second receivedmessage comprising a fifth token, as being transmitted by the second STAand acknowledging receipt of the second FTM message based, at least inpart, on a comparison of the fifth token to a value computed as afunction of the first token and the fourth token.
 16. The first STA ofclaim 9, wherein the first FTM message is transmitted in response toreceipt of an FTM request message transmitted from the second STA, andwherein the FTM request message comprises a value in a “Trigger” fieldspecifying authentication of messages acknowledging receipt of FTMmessages.
 17. A first wireless transceiver device, comprising: means fortransmitting a first fine timing measurement (FTM) message addressed toa second wireless transceiver device; and means for conditionallyauthenticating a received message as being transmitted by the secondwireless transceiver device and acknowledging receipt of the first FTMmessage.
 18. The first wireless transceiver device of claim 17, andfurther comprising: means for transmitting a second FTM messageaddressed to the second wireless transceiver device comprising one ormore parameters indicating a time of arrival of the received message inresponse to authenticating the received message as being transmitted bythe second wireless transceiver device and acknowledging receipt of thefirst FTM message.
 19. The first wireless transceiver device of claim17, wherein the means for conditionally authenticating the receivedmessage as being transmitted by the second wireless transceiver deviceand acknowledging receipt of the first FTM message comprises means forauthenticating the received message based, at least in part, on one ormore parameters in the received message indicating a source device. 20.The first wireless transceiver device of claim 19, wherein the one ormore parameters are indicative of a BSSID of the second wirelesstransceiver device.
 21. The first wireless transceiver device of claim17, wherein the received message comprises one or more parametersindicating a time that the first FTM message is received at the secondwireless transceiver device and a time that the received message istransmitted from the second wireless transceiver device, and wherein themeans for conditionally authenticating the received message as beingtransmitted by the second wireless transceiver device and acknowledgingreceipt of the first FTM message further comprises means for comparing atime of arrival of the received message with a value based, at least inpart, on the one or more parameters indicating the time that the firstFTM message is received at the second wireless transceiver device andthe time that the received message is transmitted from the secondwireless transceiver device.
 22. The first wireless transceiver deviceof claim 17, wherein the first FTM message is transmitted in response toreceipt of an FTM request message from the second wireless transceiverdevice comprising a first token, the first FTM message comprises asecond token and the received message comprises a third token, andwherein the means for conditionally authenticating the received messageas being transmitted by the second wireless transceiver device andacknowledging receipt of the first FTM message further comprises meansfor comparing the third token to a value computed as a function of thefirst token and the second token.
 23. The first wireless transceiverdevice of claim 17, wherein the first FTM message is transmitted inresponse to receipt of an FTM request message transmitted from thesecond wireless transceiver device, and wherein the FTM request messagecomprises a value in a “Trigger” field specifying authentication ofmessages acknowledging receipt of FTM messages.
 24. A non-transitorystorage medium comprising computer readable instructions stored thereonwhich are executable by a processor of a first wireless transceiverdevice to: initiate transmission of a first fine timing measurement(FTM) message, the first FTM message being addressed to a secondwireless transceiver device; and conditionally authenticate a receivedmessage as being transmitted by the second wireless transceiver deviceand acknowledging receipt of the first FTM message.
 25. The storagemedium of claim 24, further comprising instructions executable by theprocessor to: initiate transmission of a second FTM message addressed tothe second wireless transceiver device comprising one or more parametersindicating a time of arrival of the received message in response toauthenticating the received message as being transmitted by the secondwireless transceiver device and acknowledging receipt of the first FTMmessage.
 26. The storage medium of claim 24, further comprisinginstructions executable by the processor to conditionally authenticatethe received message as being transmitted by the second wirelesstransceiver device and acknowledging receipt of the first FTM message byauthenticating the received message based, at least in part, on one ormore parameters in the received message indicating a source device. 27.The storage medium of claim 26, wherein the one or more parameters areindicative of a BSSID of the second wireless transceiver device.
 28. Thestorage medium of claim 24, wherein the received message comprises oneor more parameters indicating a time that the first FTM message isreceived at the second wireless transceiver device and a time that thereceived message is transmitted from the second wireless transceiverdevice, and wherein the instructions are further executable by theprocessor to conditionally authenticate the received message as beingtransmitted by the second wireless transceiver device and acknowledgingreceipt of the first FTM message by comparing a time of arrival of thereceived message with a value based, at least in part, on the one ormore parameters indicating the time that the first FTM message isreceived at the second wireless transceiver device and the time that thereceived message is transmitted from the second wireless transceiverdevice.
 29. The storage medium of claim 24, wherein the first FTMmessage is transmitted in response to receipt of an FTM request messagefrom the second wireless transceiver device comprising a first token,the first FTM message comprises a second token and the received messagecomprises a third token, and wherein the instructions are furtherexecutable by the processor to conditionally authenticate the receivedmessage as being transmitted by the second wireless transceiver deviceand acknowledging receipt of the first FTM message by comparing thethird token to a value computed as a function of the first token and thesecond token.
 30. The storage medium of claim 24, wherein the first FTMmessage is transmitted in response to receipt of an FTM request messagetransmitted from the second wireless transceiver device, and wherein theFTM request message comprises a value in a “Trigger” field specifyingauthentication of messages acknowledging receipt of FTM messages.